1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method, and more particularly, to technology for preventing decline in image quality caused by variation in the speed of an intermediate transfer body when forming an image on the intermediate transfer body in the image forming apparatus which uses a transfer method by which an image is formed on the intermediate transfer body by means of a liquid ejection device, such as an inkjet head, and the image is then transferred to a recording medium.
2. Description of the Related Art
In an inkjet recording apparatus which uses a transfer method in which an image is formed on an intermediate transfer body from an inkjet head and then transferred to a recording medium, a desired image is formed on the intermediate transfer body by ejecting ink at prescribed timing while moving the intermediate transfer body at a prescribed speed. When a load is placed on the intermediate transfer body, for instance, when the image is being transferred from the intermediate transfer body to the recording medium, or when the intermediate transfer body is being cleaned, then a speed variation occurs in the intermediate transfer body, even if the drive source of the intermediate transfer body is controlled to a uniform speed. When an image is formed by an inkjet head on the intermediate transfer body, in a state where speed variation occurs in the intermediate transfer body in this way, then displacement occurs in the positions at which the dots are formed, due to the speed variation of the intermediate transfer body directly below the inkjet head, and therefore the image quality is markedly degraded. In order to resolve this problem, various methods have been proposed for preventing decline in the image quality caused by speed variation of the intermediate transfer body in an image forming apparatus based on a transfer method which uses the intermediate transfer body.
Japanese Patent Application Publication No. 2000-326559 discloses an invention related to a transfer type of inkjet recording apparatus in which deterioration of image quality is prevented by avoiding use of devices which are involved in image formation, such as a device which applies treatment liquid to the intermediate transfer body, a transfer device, a separating device, during image recording by the inkjet head.
However, in the invention described in Japanese Patent Application Publication No. 2000-326559, since image formation onto the intermediate transfer body is halted during transfer or cleaning. Although this is effective in preventing image deterioration, productivity is adversely affected.